Method and system for quantifying the performance of network component

ABSTRACT

A method and system for quantifying the performance of a component adapted to function as a node in a communications network where the component is represented by a virtual distance (x) according to the following formula:  
       x   =         S     i   +   1       -     S   i       IS         
where the virtual distance x is a representation of a metric that relates to intrinsic properties of the component.

FIELD OF INVENTION

The present invention relates to a method and a system for quantifyingthe performance of a component adapted to function as a node in acommunications network. The service time delay for an information unitwith a certain payload is known as the time difference between the timeof departure of the information unit and the time of arrival of theinformation unit. A first service time is known for a first informationunit with a first payload, a second service time is known for a secondinformation unit with a second payload, and so on to a last informationunit with a last payload, where the incremental step of payload betweenthe first, second and following information units is predefined.

The present invention also relates to various computer program productswhereby an inventive method or system can be realised.

DESCRIPTION OF BACKGROUND ART

Network technology is spreading rapidly and the amount of systems actingas nodes in a communications network are increasing. The users of thesenodes are changing from skilled technicians to computer users in smallcompanies or private users in their homes.

There is an increasing need to provide users with possibilities toevaluate and compare network components without advanced knowledge innetwork communications.

Manufacturers of components used as nodes in a communications network,such as switches, routers, servers or access points and the like,usually measure performance variables that are considered relevant andlist these in data sheets. The variables measured and presented varyfrom manufacturer to manufacturer, and it is often very hard to compareperformance of two components from different manufacturers.

Various benchmarking techniques through which certain aspects of theperformance of a network component can be evaluated are known.

Patent publication WO 02 51181 A1 shows a benchmark testing a networknode in a radio communication network. The testing of the node pertainsto load and stress testing.

Patent publication EP 0 849 911 A2 shows a method of monitoring acommunications network comprising a plurality of node equipment.

The publication “Wireless LAN Access Points as Queuing Systems:Performance Analysis and Service Time”, by Al Khatib et al, published 18Dec. 2002, shows a way to measure various parameters of an access pointin a communications network.

SUMMARY OF THE PRESENT INVENTION

Problems

It is a problem to provide a possibility to quantify the performance ofan arbitrary component adapted to function as a node in a communicationsnetwork so that it can be compared with any other component adapted tofunction as a node in a communications network.

It is a problem to find a metric that corresponds to such quantificationand that relates to intrinsic properties of the component, i.e. that isconstant with respect to time, surroundings and other variables, inother words, it is a problem to provide a simple benchmarking techniqueto quantify quality of communication nodes as there is a Horse Power formotors, or Million Instructions Per Second (MIPS) for microprocessors,or Standby Battery Lifetime for a mobile phone.

It is also a problem to find a metric that can be used to quantifycomponents with different characteristics for different senses, such asuplink and downlink communication, or with many different input and/oroutput interfaces that can be combined in different ways, thus havingdifferent characteristics for different combinations of interfaces.

Solution

With the purpose of solving one or more of the above indicated problems,and from the standpoint of the above indicated field of invention, thepresent invention teaches that the component is represented by a virtualdistance according to the following formula:x=v ₁ ·S ₁ =v ₂ ·S ₂ =. . . =v ₁ ·S _(i) =v _(i+1) ·S _(i+1) =. . . =v_(n) ·S _(n)where the virtual distance x is a constant distance for a givencomponent.

The parameter v_(i) corresponds to a virtual speed with which aninformation unit with a specific payload travels. The parameter S_(i)corresponds to the time taken to travel the distance x with the speedv_(i), S_(i) being the service time for an information unit with aspecific payload. The speed v_(i) is represented by:$v_{i} = {\lbrack {\frac{S_{i + 1}}{S_{i}} - 1} \rbrack \cdot {IS}^{- 1}}$and the constant distance x thus is represented by:$x = \frac{S_{i + 1} - S_{i}}{IS}$where a predefined incremental step IS is the difference of payloadbetween the first, second and following information units. The virtualdistance x is a representation of a metric that relates to intrinsicproperties of the component, allowing a quantification of the component.

With the purpose of allowing a quantification of a component that isadapted to communicate in two directions, the present invention teachesthat two distances represent the component. A first distance representsthe component in a first sense, meaning that the information unitsarrive to the component through a first interface and departs from thecomponent through a second interface, such as uplink communication. Asecond distance represents the component in a second sense, meaning thatthe information units arrive to the component through the secondinterface and departs from the component through the first interface,such as downlink communication.

If the component has a number of usable interfaces, then the presentinvention teaches that the component is represented by two distances,meaning two senses, for every possible combination of interfaces.

The present invention teaches that the service time is a part of acomponents total response time (R), that the response time (R) is a sumof the service time (S) and a waiting time (W), thatR_(i)=t_(di)−t_(ai). If t_(ai)≧t_(d(i−1))then W_(I)=0 and S_(i)=R_(i),and if t_(ai)<t_(d(i−1)) then W_(i)=t_(d(i−1))−t_(ai) andS_(i)=t_(di)−t_(d(i−1)).

The service time comprises the time to process, to check for errors andto transmit an information unit, and the time to process an informationunit may indude any management time and other delays relating to networkspecific details.

The present invention teaches that statistical methods are used toobtain values for service times, and thus virtual speed, representinginformation units with different payloads, and virtual distancerepresenting the component, with sufficient accuracy and certainty.

Advantages

The advantages of a method, system, a single computing unit or anycomputer program product according to the present invention are that thepresent invention will provide a metric that relates to intrinsicproperties of the component, allowing a quantification of a componentthat makes the component comparable with the same quantification of anentirely different kind of component.

The quantification according to the invention can be made on anycomponent adapted to function as a node in a communications network.

The results gotten from the statistical calculations on the quality of aunit according to the present invention are repeatable; unlike thebenchmarking techniques that exist on networking that differ in theirresults from one hour in the day to another.

BRIEF DESCRIPTION OF THE DRAWINGS

A method, a system, various computer program products and a singlecomputing unit according to the present invention will now be describedin detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic and simplified illustration of a first embodimentof a method and system according to the present invention, adapted to acomponent with a first and second interface for communication,

FIG. 2 is a schematic and simplified illustration of a second embodimentof a method and system according to the present invention, adapted to acomponent with a number of different usable interfaces forcommunication, and

FIG. 3 is a schematic and simplified illustration of an embodiment ofthe present invention where a single computing unit is adapted toperform the functions of both the first, second and third computingunits according to previous embodiments.

DESCRIPTION OF EMBODIMENTS AS PRESENTLY PREFERRED

The present invention will now be described with reference to FIG. 1showing a component 1 adapted to function as a node in a communicationsnetwork. This component 1 is connected to a first computing unit 2 and asecond computing unit 3, thus forming a simulation of a networkenvironment. The present invention relates to a method for quantifyingthe performance of the component 1.

The performance of the component is evaluated from a situation where amessage, in the following described as an information unit, which forexample could be a packet in a packet switched network, is sent from thefirst or second computing unit to the other of the first or secondcomputing units through the component 1. A third computing unit 4, notbeing a part of the communication path, is monitoring differentparameters pertaining to the communication and respective informationunit.

The following parameters are definitions that are used in the inventivemethod or system. The service time delay S for an information unit Awith a certain payload P is known as the time difference between thetime of departure t_(d) from the component 1 of the information unit Aand the time of arrival t_(a) to the component 1 of the information unitA, where a first service time S₁ is known for a first information unitA₁ with a first payload P₁, a second service time S₂ is known for asecond information unit A₂ with a second payload P₂, and so on to a lastinformation unit A_(n) with a last payload P_(n).

A stream of information units 5, in the figure schematically illustratedwith blocks of different sizes, are sent with a predefined incrementalstep IS of payload between the first, second and following informationunits A₁, A₂, . . . , A_(i), . . . , A_(n) in the stream of information.

The present invention specifically teaches that the component isrepresented by a virtual distance x according to the following formula:x=v ₁ ·S ₁ =v ₂ ·S ₂ =. . . =v _(i) ·S _(i) =v _(i+1) ·S _(i+1) =. . .=v _(n) ·S _(n)

where the virtual distance x is a constant distance for a givencomponent, where v_(i); corresponds to a virtual speed with which aninformation unit A_(i) with a specific payload P_(i) travels, and S_(i)corresponds to the time taken to travel the distance x with the speedv_(i), S_(i) being the service time for an information unit A_(i) withpayload P_(i).

The virtual speed v is a function of the payload P, very much in thesame way as the speed of a real vehicle is a function of its load wherethe speed decreases as the load increases. The following model of thisdependency is set up in order to arrive at a dependency between speedand payload: $v_{i} = \frac{1}{P_{i} + \beta}$where$\beta = {{\frac{IS}{m - 1} - {P_{i}\quad{and}\quad m}} = \frac{S_{i + 1}}{S_{i}}}$

This gives us that the speed v_(i) is represented by:$v_{i} = {\frac{1}{P_{i} + \lbrack {\frac{IS}{m - 1} - P_{i}} \rbrack} = {\frac{m - 1}{IS} = {\frac{\frac{S_{i + 1}}{S_{i}} - 1}{IS} = {\lbrack {\frac{S_{i + 1}}{S_{i}} - 1} \rbrack \cdot {IS}^{- 1}}}}}$

The virtual distance x is thus represented by:$x = \frac{S_{i + 1} - S_{i}}{IS}$

This gives us that the virtual distance x is a representation of aconstant metric that relates to intrinsic properties of the component,allowing a quantifycation of the component whereby the component can becompared with any other component quantified in the same way.

FIG. 1 shows that the component 1 communicates through two differentinterfaces, a first interface 1 a, in the figure exemplified with aninterface for wire bound communication, and a second interface 1 b, inthe figure exemplified with an interface for wireless communication.

The present invention teaches that such a component is represented bytwo distances, where a first distance _(a)x represents the component ina first sense, meaning that as the information units arrive to thecomponent 1 through the first interface 1 a and departs from thecomponent 1 through the second interface 1 b, such as uplinkcommunication. A second distance _(b)x represents the component 1 in asecond sense, meaning that the information units arrive to the component1 through the second interface 1 b and departs from the component 1through the first interface 1 a, such as downlink communication.

FIG. 2 shows a component 1 with a number of usable interfaces 1 a, 1 b,. . . , 1 n, for communication. The present invention teaches that twodistances, meaning two senses, for every possible combination ofinterfaces for input and output communication, represent such acomponent.

Service time can be defined in different ways and quantificationaccording to the present invention should give a result that is notdependent on other network characteristics then the actualcharacteristics of the component.

The service time S according to the present invention is thus a part ofa component's total response time R, where the response time R is a sumof the service time S and a waiting time W. The response time is thusdefined as R_(i)=t_(di)−t_(ai).

If t_(ai) ≧t_(d(i−1)) then W_(i)=0 and S_(i)=R_(i), and ift_(ai)<t_(d(i−1)) then W_(i)=t_(d(i−1))−t_(ai) andS_(i)=t_(di)−t_(d(i−1)).

The present invention teaches that the service time S comprises the timeto process, to check for errors and to transmit an information unit A,and that the time to process an information unit A may include anymanagement time and other delays relating to network specific details.

Since a method or system according to the invention is to be used fornon ideal components it is proposed that statistical methods are used toobtain values for service times S, and thus virtual speed v,representing information units A with different payloads P, and virtualdistance x representing the component 1, with sufficient accuracy andcertainty.

The present invention also relates to a system for quantifying theperformance of a component 1 adapted to function as a node in acommunications network. With renewed reference to FIG. 1, the systemcomprises a first, second and third computing unit, where the firstcomputing unit 2 is connected to the component 1 by means of a firstinterface 1 a, and where the second computing unit 3 is connected to thecomponent 1 by means of a second interface 1 b. Both the first andsecond computing units 2, 3 comprises means for communication 21, 31 andinterfaces for communication 2 a, 3 a according to different standard ofcommunication in a network environment.

The first computing unit 2 is adapted to send an information unit A witha certain payload P to the second computing unit 3 through the component1.

The third computing unit 4 is adapted to use the information obtained bycalculating the service time delay S for the information unit A bymeasuring the time difference between the time of departure t_(d) of theinformation unit A from the component 1 and the time of arrival t_(a) ofthe information unit A to the component 1.

The first computing unit 2 is adapted to send a stream of informationunits 5 to the second computing unit 3 through the component 1, wherethe incremental step IS of payload between a first, second and followinginformation units A₁, A₂, . . . , A_(i), . . . , A_(n) is predefined.

The third computing unit 4 is adapted to measure a first service time S₁for a first information unit A₁ with a first payload P₁, a secondservice time S₂ for a second information unit A₂ with a second payloadP₂, and so on to a last information unit A_(n) with a last payload P_(n)in the stream of information units.

The present invention teaches that the component 1 is represented by avirtual distance x, and that the third computing unit 4 is adapted tocalculate the virtual distance according to the following formula:x=v ₁ ·S ₁ =v ₂ ·S ₂ =. . . =v _(i) ·S _(i) =v _(i+1) ·S _(i+1) =. . .=v _(n) ·S _(n)

where the virtual distance x is a constant distance for a givencomponent 1.

The parameter v_(i) corresponds to a virtual speed with which aninformation unit A_(i) with a specific payload P_(i) travels, and S_(i)corresponds to the time taken to travel the distance x with the speedv_(i), S_(i) being the service time for an information unit A_(i) withpayload P_(i), that the speed v_(i); is represented by:$v_{i} = {\lbrack {\frac{S_{i + 1}}{S_{i}} - 1} \rbrack \cdot {IS}^{- 1}}$and the constant distance x thus is represented by:$x = \frac{S_{i + 1} - S_{i}}{IS}$

The third computing unit 4 is adapted to present the virtual distance xas a representation of a metric that relates to intrinsic properties ofthe component 1, thus providing the quantification of the component 1.

According to one preferred embodiment is the third computing unit 4adapted to calculate two distances representing the component 1. A firstdistance _(a)x represents the component 1 in a first sense, where thefirst computing unit 2 is, adapted to send information units to thesecond computing unit 3 through the component 1, the first computingunit 2 thus being adapted to act as a sending computing unit and thesecond computing unit 3 thus being adapted to act as a receivingcomputing unit, such as uplink communication, and where a seconddistance _(b)x represents the component 1 in a second sense, where thesecond computing 3 unit is adapted to send packets to the firstcomputing 2 unit through the component 1, the second computing unit 3thus being adapted to act as a sending computing unit and the firstcomputing unit 2 thus being adapted to act as a receiving computingunit, such as downlink communication.

FIG. 2 shows an embodiment where the component 1 has a number of usableinterfaces 1 a, 1 b, . . . , 1 n. The present invention teaches that inthis case, the first and second computing units 2, 3 are adapted tocommunicate with each other through the component 1 through everypossible combination of interfaces, and that the third computing unit 4is adapted to calculate and present two distances representing thecomponent 1, meaning two senses, for every possible combination ofinterfaces.

The third computing unit 4 is adapted to extract the service time S fromthe total response time of the component. The response time R is a sumof the service time S and a waiting time W of the component, whereR_(i)=t_(di)−t_(ai).

If t_(ai)≧t_(d(i−1)) then W_(i)=0 and S_(i)=R_(i), and that ift_(ai)<t_(d(i−1)) then W_(i)=t_(d(i−1))−t_(ai) andS_(i)=t_(di)−t_(d(i−1)).

It is also proposed that the service time S comprises the time toprocess, to check for errors and to transmit an information unit A, andthat the time to process an information unit A may include anymanagement time and other delays relating to network specific details.

The present invention teaches that the first and second computing units2, 3 are adapted to send and receive several streams of informationunits through the component 1, each stream being sufficiently long torepresent information units A with different payloads P, in order toprovide the third computing unit 4 with measurement data required toperform statistical methods to obtain values for service times S,virtual speed v and virtual distance x with sufficient accuracy andcertainty.

The present invention also relates to a number of computer programproducts, schematically illustrated in FIG. 1.

A first computer program product C1 comprises first computer programcode C1′, which, when executed by a computing unit, makes the computingunit work as an inventive first computing unit 2.

A second computer program product C2 comprises second computer programcode C2′, which, when executed by a computing unit, makes the computingunit work as an inventive second computing unit 3.

A third computer program product C3 comprises third computer programcode C3′, which, when executed by a computing unit, makes the computingunit work as an inventive third computing unit 4.

A fourth computer program product C4, shown in FIG. 3, comprises fourthcomputer program code C4′, which, when executed by a computing unit,makes the computing unit perform the above described inventive method.

FIG. 3 shows schematically an embodiment with a single computing unit 6,a Quantifying Performance Unit, QPU, for quantifying the performance ofa component 1 adapted to function as a node in a communications network.

The single computing 6 unit is adapted to function as both an inventivefirst, second and third computing unit 2, 3, 4, these units shown indotted lines in the figure, where the single unit 6 comprises requiredinterfaces 6 a, 6 b and means for communication to perform the functionsof the inventive first, second and third computing units 2, 3, 4.

According to one embodiment, the single computing unit 6 comprisescomputer program code C4′ according to the inventive fourth computerprogram product C4.

It is also possible to let the single computing 6 unit comprise computerprogram code C1′, C2′, C3′ according to the inventive first, second andthird computer program product C1, C2, C3.

It will be understood that the invention is not restricted to theaforedescribed and illustrated exemplifying embodiments thereof and thatmodifications can be made within the scope of the inventive concept asillustrated in the accompanying Claims.

1. Method for quantifying the performance of a component (1) adapted tofunction as a node in a communications network, where the service timedelay (S) for an information unit (A) with a certain payload (P) isknown as the time difference between the time of departure (t_(d)) ofsaid information unit (A) and the time of arrival (t_(a)) of saidinformation unit (A), where a first service time (S₁) is known for afirst information unit (A₁) with a first payload (P₁), a second servicetime (S₂) is known for a second information unit (A₂) with a secondpayload (P₂), and so on to a last information unit (A_(n)) with a lastpayload (P_(n)) in a stream of payloads, and where the incremental step(IS) of payload between said first, second and following informationunits (A₁, A₂, . . . , A_(n)) is predefined, characterized in, that saidcomponent is represented by a virtual distance (x) according to thefollowing formula:x =v ₁ ·S ₁ =v ₂ ·S ₂ =. . . =v _(i) =S _(i) =v _(i+1) ·S _(i+1) =. . .=v _(n) ·S _(n) that the virtual distance x is a constant distance for agiven component, that v_(i) corresponds to a virtual speed with which aninformation unit (A_(i)) with a specific payload P_(i) travels, thatS_(i) corresponds to the time taken to travel said distance x with thespeed v_(i), S_(i) being the service time for an information unit A_(i)with payload P_(i), that the speed v_(i) is represented by:$v_{i} = {\lbrack {\frac{S_{i + 1}}{S_{i}} - 1} \rbrack \cdot {IS}^{- 1}}$that the constant distance x thus is represented by:$x = \frac{S_{i + 1} - S_{i}}{IS}$ and that the virtual distance x is arepresentation of a metric that relates to intrinsic properties of saidcomponent, allowing said quantification of said component.
 2. Methodaccording to claim 1, characterised in, that said component (1) isrepresented by two distances, that a first distance _(a)x representssaid component in a first sense, meaning that as said information unitsarrive to said component (1) through a first interface (1 a) and departsfrom said component (1) through a second interface (1 b), such as uplinkcommunication, and that a second distance _(b)x represents saidcomponent (1) in a second sense, meaning that said information unitsarrive to said component (1) through said second interface (1 b) anddeparts from said component (1) through said first interface (1 a), suchas downlink communication.
 3. Method according to claim 1 or 2,characterised in, that, if said component (1) has a number of usableinterfaces (1 a, 1 b, . . . , 1 n), then said component is representedby two distances, meaning two senses, for every possible combination ofinterfaces.
 4. Method according to any preceding claim, characterisedin, that said service time (S) is a part of a components total responsetime (R), that the response time (R) is a sum of said service time (S)and a waiting time (W), that R_(i)=t_(di)−t_(ai), that ift_(ai)≧t_(d(i−1)) then W_(i)=0 and S_(i)=R_(i), and that ift_(ai)<t_(d(i−1)) then W_(i)=t_(d(i−1))−t_(ai) andS_(i)=t_(di)−t_(d(i−1)).
 5. Method according to any preceding claim,characterised in, that said service time (S) comprises the time toprocess, to check for errors and to transmit an information unit (A),and that the time to process an information unit (A) may include anymanagement time and other delays relating to network specific details.6. Method according to any preceding claim, characterised in, thatstatistical methods are used to obtain values for service times (S), andthus virtual speed (v), representing information units (A) withdifferent payloads (P), and virtual distance (x) representing saidcomponent (1), with sufficient accuracy and certainty.
 7. System forquantifying the performance of a component (1) adapted to function as anode in a communications network, said system comprising a first, secondand third computing unit, where said first computing unit (2) isconnected to said component (1) by means of a first interface (1 a),where said second computing unit (3) is connected to said component (1)by means of a second interface (1 b), where said first computing unit(2) is adapted to send an information unit (A) with a certain payload(P) to said second computing unit (3) through said component (1), wheresaid third computing unit (4) is adapted to passively calculate theservice time delay (S) for said information unit (A) by using theinformation obtained by measuring the time difference between the timeof departure (t_(d)) of said information unit (A) from said component(1) and the time of arrival (t_(a)) of said information unit (A) to saidcomponent (1), where said first computing unit (2) is adapted to send astream of information units where the incremental step (IS) of payloadbetween a first, second and following information units (A₁, A₂, . . . ,A_(n)) is predefined, where said third computing unit (4) is adapted tomeasure a first service time (S₁) for a first information unit (A₁) witha first payload (P₁), a second service time (S₂) for a secondinformation unit (A₂) with a second payload (P₂), and so on to a lastinformation unit (A_(n)) with a last payload (P_(n)) in said stream ofinformation units, characterized in, that said component (1) isrepresented by a virtual distance x, that said third computing unit (4)is adapted to calculate said virtual distance according to the followingformula:x =v ₁ ·S ₁ =v ₂ ·S ₂ =. . . =v _(i) ·S _(i) =v _(i+1) ·S _(i+1) =. . .v _(n) ·S _(n) that said virtual distance x is a constant distance for agiven component (1), that v_(i) corresponds to a virtual speed withwhich an information unit (A_(i)) with a specific payload (P_(i))travels, that S_(i) corresponds to the time taken to travel saiddistance x with the speed v_(i), S_(i) being the service time for aninformation unit A_(i) with payload P_(i), that the speed v_(i) isrepresented by:$v_{i} = {\lbrack {\frac{S_{i + 1}}{S_{i}} - 1} \rbrack \cdot {IS}^{- 1}}$that the constant distance x thus is represented by:$x = \frac{S_{i + 1} - S_{i}}{IS}$ and that said third computing unit(4) is adapted to present the virtual distance x as a representation ofa metric that relates to intrinsic properties of said component (1),thus providing said quantification of said component (1).
 8. Systemaccording to claim 7, characterised in, that said third computing unit(4) is adapted to calculate two distances representing said component(1), that a first distance _(a)x represents said component (1) in afirst sense, where said first computing unit (2) is adapted to sendinformation units to said second computing unit (3) through saidcomponent (1), such as uplink communication, and that a second distance_(b)x represents said component (1) in a second sense, where said secondcomputing (3) unit is adapted to send packets to said first computing(2) unit through said component (1), such as downlink communication. 9.System according to claim 7 or 8, characterised in, that, if saidcomponent (1) has a number of usable interfaces (1 a, 1 b, . . . , 1 n),then said first and second computing units (2, 3) are adapted tocommunicate with each other through said component (1) through everypossible combination of interfaces, and that said third computing unit(4) is adapted to calculate and present two distances representing saidcomponent (1), meaning two senses, for every possible combination ofinterfaces.
 10. System according to claim 7, 8 or 9, characterised in,that said third computing unit (4) is adapted to extract said servicetime (S) from the total response time of said component, where theresponse time (R) is a sum of said service time (S) and a waiting time(W) of said component, that R_(i)=t_(di)−t_(ai), that ift_(ai)≧t_(d(i−1)) then W_(i)=0 and S_(i)=R_(i), and that ift_(ai)<t_(d(i−1)) then W_(i), =t_(d(i−1)−t) _(ai) andS_(i)=t_(di)−t_(d(i−1)).
 11. System according to any one of claims 7, 8,9 or 10, characterised in, that said service time (S) comprises the timeto process, to check for errors and to transmit an information unit (A),and that the time to process an information unit (A) may include anymanagement time and other delays relating to network specific details.12. System according to any one of claims 7, 8, 9, 10 or 11,characterised in, that said first and second computing units (2, 3) areadapted to send and receive several streams of information units throughsaid component (1), each stream being sufficiently long to representinformation units (A) with different payloads (P), in order to providesaid third computing unit (4) with measurement data required to performstatistical methods to obtain values for service times (S), virtualspeed (v) and virtual distance (x) with sufficient accuracy andcertainty.
 13. A first computer program product, characterised in, thatsaid first computer program product comprises first computer programcode, which, when executed by a computing unit, makes said computingunit work as a first computing unit according to any one of claims 7 to12.
 14. A second computer program product, characterised in, that saidsecond computer program product comprises second computer program code,which, when executed by a computing unit, makes said computing unit workas a second computing unit according to any one of claims 7 to
 12. 15. Athird computer program product, characterised in, that said thirdcomputer program product comprises third computer program code, which,when executed by a computing unit, makes said computing unit work as athird computing unit according to any one of claims 7 to
 12. 16. Afourth computer program product, characterised in, that said fourthcomputer program product comprises fourth computer program code, which,when executed by a computing unit, makes said computing unit perform themethod according to any one of claims 1 to
 6. 17. Single computing unit(6) for quantifying the performance of a component (1) adapted tofunction as a node in a communications network, characterised in, thatsaid single computing (6) unit is adapted to function as both a first,second and third computing unit (2, 3, 4) according to any one of claims7 to
 12. 18. Single computing unit (6) according to claim 17,characterised in, that said single computing unit (6) comprises computerprogram code according to claim
 16. 19. Single computing unit (6)according to claim 17, characterised in, that said single computing (6)unit comprises computer program code according to claims 13, 14 and 15.